Temperature regulated cooling circuit



Dec. 28, 1948. F. wxEsENDANGER TEMPERATURE REGULATED COOLING CIRCUIT Filed Oct. 1'?, 1944 xNvENToR FR/TZ W/EJENDHNGE/ ATTORN EY5 Patented Dec. 28, 1948 TEMPERATURE REGULATED COOLING CIRCUIT Fritz Wiesendanger. Winterthur, Switzerland, assignor to Sulzer Frres Socit Anonyme, Winterthur, Switzerland Application October ll', 1944, Serial No. 559,080 In Switzerland February 8. 1944 7 claims. l

This invention relates to a system for cireulating a iluid requiring to be cooled controlled by the temperature of the circulating iluid, in particular to the cooling-water or lubricating-oil fcircuits of an internal combustion engine in which a device is employed to redeliver the iluid, when below a certain temperature. to the internal combustion engine without cooling. and to conduct the fluid, when over a certain temperature, to a cooler. The invention consists in that, for changing over to service with or without a cooler the flow-changing device provided as conditions may require, has no stable position of transition. The system employing this device should be arranged so that when in service with the cooler cut out that element is drained of uid.

For a preferred form of the now-changing device, a valve operated by a servomotor may be provided, the control member of this valveY being designed in two parts. One part of the control member may follow the movements of an expansion body and the second part may have a travel limited relatively to the ilrst part by means of stops provided on this first part. 'I'he admission and discharge openings for the control medium may be arranged in the casing of the control member in such a way that the part of the control member not connected to the expansion body moves immediately from one stop to the other of the other control member part when the control edge of the former part begins to open or completely closes the pressure medium admission and thus rapidly frees a large crosssection of now for the admission or discharge respectively of the control medium to or from the servomotor piston of the valve.

Devices dependent on temperature are known which influence the circulation of the uid to be cooled in such a way that above a certain temperature all the iluid, for instance the coolingwater. is conducted to the cooler, while under this temperature it bypasses the cooler and flows again to the internal combustion engine. These devices, however. have the disadvantage that the change-over takes place gradually, which may lead to trouble in service for the following reasons. When the temperature of the iluid lies below freezing point and the device frees the passage from one pipe to the other only gradually. the heat supplied to the cooler through the water, when the pipe to the cooler is almost closed, is so small in proportion to the heat led oil in the cooler at a certain water temperature that the water freezes within a very short time.

Ii then the device gradually opens wider the admission to this pipe, the cooler may already be so badly frozen that practically no water now ilows through it. The stoppage of circulation does not only render it impossible for the cooler to thaw out again but may also lead to serious damage in the cooler or in the internal combustion engine as a result of the great increase in temperature of the cooling-water. The provision of a device dependent on the temperature as proposed in the invention eliminates this disadvantage in that the changeover from one pipe to the other is not effected gradually but rapidly and without any stable position of transition. Moreover, when the cooler is not on strea it is drained. It is thus suiliciently ensured that so much water tlows through the cooler whenever water ows at all that the freezing-up oi the latter is impossible.

The advantage oi this invention is apparent, however, not only with water but also with lubricating oil, since this can cool down to such an extent. when the quantity flowing through the cooler is very small, that as a result of the increase in viscosity the resistance oi' the cooler reaches so high a value that the pressure in the oil system becomes too high, that is to say. that the oil, instead oi.' flowing through the cooler, ows oil by way of a sai'ety valve in order to prevent the cooler being damaged as a. result of inadmissibily high pressure. The rewarming of the oil stuck in the cooler would thus be rendered impossible and the oil temperature elsewhere in the system would rise inadmissibly high.

An embodiment of the invention. applied `to the cooling system of an internal combustion engine, is shown diagrammatically in the drawings, in which:

Fig. l illustrates in section the flow-changing device of this invention, in one operating position, arranged according to the system of this invention in a diagrammatically illustrated complete cooling plant; and

Figs. 2-4 show the temperature-controlled, low-changing device of this system in three further operating positions.

In the system as shown in Fig. l, a coolingwater pump i draws water from a collector 1, delivers it through a pipe 2 into the water jacket of an internal combustion engine 3 and from there through a pipe l to the temperature-controlled. now-changing device 5. According to the working position of the device E, the water passes (at high temperature) through a pipe 8, a cooler or radiator 9 and a pipe IB back to the collector 'I, or it ows (at low temperature) through a pipe 6 direct to the collector 'I and the cooler 9 stands emptied. In the arrangement illustrated in Fig. l, the radiator empties by gravity into the collector l. as it would in the ordinary automobile cooling plant. No difllculty will be met by those skilled in the art in providing other means of emptying should gravity not be available in a particular installation.

Inside of the device 5 is a valve II which is operated by the piston I2 acting as a servomotor piston and which controls the admission of water to the pipes 6 or 8. The control of the piston I2 is eil'ected by the two-piece slide valve I4, I5, which in lts turn is actuated by the expansion body 2 I The method of working o! the deviceis as follows:

When the engine I is put in service with cold cooling-water and the pump I runs. cold water news over the temperature gauge 23. The medium present in the expansion body 2l, for instance uid, then takes up its smallest space, so that the valve Il is pressed downwards by the spring 25 and the valve I5 stops the supply out of the pipe I5 (Fig. 4). No pressure then prevails in the space IB above the piston I2. as the control medium present in this space can escape at I9 and pass through the passages I1, II in the valve I4 and through the pipe 2l. The spring I3 thus pressed the valve Il upwards. so that its base comes to lie against the upper seat II' and thus connects the pipe 4 with the pipe B.

If the temperature of the cooling-water now gradually rises, the tluid 22 expands the body 2l upwards and presses the valves I4, I5 upwards. There is no change, however. in the position oir the valve II, until the valves Il, I5 have arrived in the position which is shown in Fig. 1. If the temperature of the cooling-water rises higher, the valves I4, I5 also rise, so that pressure medium can pass from the pipe I5 into the space 25. The valve I5 is then lifted from the valve I4 and takes up the position shown in Fig. 2. It thusimmediately frees a large cross-section of flow for the admission of the pressure medium to the piston I 2, so that the piston I2 moves downwards rapidly, that is without there being any stable position of transition, and brings the valve I I immediately into its lower end position and thus closes the pipe 6. The water then ilows from the pipe I through the pipe 8 to the cooler B.

When the cooling-water temperature again sinks, the expansion body 2| once more contracts. The valve Il and the valve I5 move downwards initially as a unit. The downward forces acting on valve Il are then its own weight and the pressure in the space 2l. The downward forces acting on the valve I5 are then its own weight and the spring 25. The pressure in space 2li exerts an upward force on valve I5. 'I'he spring 25, moreover, is not capable oi' moving the valve I5 independently oi' the valve I4. as the pressure in the space 2li is greater than that exerted by the spring 25. On the motion of the valves Il, I5 as a unit. just described, in their relative position shown in Fig. 2, the pressure in the space 20 has no influence, as it acts upwards and downwards on the same cross-section. The valves I4, I5 thus obey only their own weight and the pressure of the spring 25. There is no change in the position of the valve II until the valve I5 has arrived in the position shown in Fig. 3. The space 20 is now cut ci! by valve I5 from the pressure pipe I6.

As this space 20 is connected with the space IB above the piston i2 but the latter is relieved by the opening coming into existence between the edge I9 and the valve I5. the pressure in the space 20 disappears and the valve I5 moves rapidly downwards until it again comes up against the valve Il as shown in Fig. 4. At the same time the spring I3 presses the piston I2 and with it the valve II rapidly and without any stable position of transition as far upwards as possible, as the pressure medium present above the piston I2 escapes through the passage I1 in the valve I4 and through the pipe 2l. The cooling-water then ows back once more, as at the beginning (Fig. 1) through the pipe 6 and the process described can begin again.

In place of the expansion body 2| lled with iluid, a solid body may also be used.

The servomotor Il, I5, I2 of the valve Il is so designed that the piston I2 is operated with pressure medium when the pipe 8 leading to the cooler 9 is opened, while the spring I3 eects the closing oi' this pipe. The servomotor can naturally be equally well designed for working with these functions interchanged.

I claim:

1. A system for circulating a fluid requiring to be cooled including, in combination, a heat source imparting heat to said fluid, a radiator, a collector, passages for passing said fluid through a circuit including said heat source, said radiator and said collector in series, a by-pass in said circuit connecting said heat source to said collector in parallel to said radiator, and controllable flowchanging means in said circuit Without a stable position of transition [or cutting said radiator in and out of the circuit, said circuit being so arranged that the radiator is emptied when none of said uid is fed to it.

2. The system for circulating a uld requiring to be cooled including, in combination, a heat source imparting heat to said fluid, a radiator, a collector, passages for passing said fluid through a circuit including said heat source, said radiator and said collector in series, a by-pass in said circuit connecting said heat source to said collector in parallel to said radiator, a dow-changing device in said circuit for changing the flow distribution through radiator and by-pass, and servomotor means without a stable position of transition controlling said flow-changing device for cutting said radiator in and out of said circuit, said circuit being so arranged that the radiator is emptied when none of said fluid is fed to it.

3. The combination of claim 2 in which the servomotor means include a source of fluid under pressure, a piston operatively connected to the flow-changing device and control means intermediate said pressure fluid source and said piston that include a two-part valve.

4. The combination of claim 3 in which the control means include an expansion body, one part of the two-part valve following the movement of said expansion body and the other part of the two-part valve having a travel limited by contact with stop portions of the ilrst part.

5. The combination of claim 2 in which the servomotor means include a casing, a source of iluid under pressure opening into said casing, a cylinder in said casing, a piston operatively connected to the flow-changing device running in said cylinder, a discharge passage leading from said casing and control means arranged within said casing that include an expansion body and a two-part valve, one part of which valve follows the movements of said expansion body and the other part of which has a travel limited by contact with stop portions of the rst part, said control means, said pressure opening and said discharge passage being so arranged that when movement of the first part of said valve causes a control edge of the second part of said valve partially to uncover either said opening or said passage, said second part moves immediately the full distance of its travel relative to said first part, thus rapidly freeing the whole available cross-sectional area of said opening or said passage for the admission or discharge of the pressure fluid to or from said piston.

6. As a sub-combination. a device including a now-through chamber having at least three flow passages thereinto, valve means for closing alternatively one or the other of a pair oi said passages. and servomotor means without a stable position of transition for shifting said valve means from the closed position for one of said pair oi passages to the closed position for the `ither.

7. As a sub-combination, a device including a flow-through chamber having at least three ow passages thereinto. valve means for closing alternatively one or the other of a pair of said passages, and a hydraulic servomotor assembly controlling said valve means, said assembly including a source of fluid under pressure. a pressure fluid discharge, a single-action. springloaded piston connected to said valve means to close one of said pair of passages under influence of fluid under pressure and the other, under intluence of the spring-loading. and means to control the fluid pressure action on said piston that include an expansion body responsive to temperature in said chamber and a two-part valve to control the passage of iuid to and from said piston from and to said pressure source and said discharge, respectively, the first part of said twopart valve being in contact with said expansion body and the second part having a travel limited by contact with stop portions of the rst part, said control means being so arranged that, when a movement of the rst part causes a control edge of the second part partially to connect said piston to either said pressure source or said discharge, said second part moves immediately the full distance of its travel relative to said first part, thus rapidly freeing the whole cross-sectional area of ow from and to said source or discharge,

respectively.

FRITZ WIESENDANGER.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,228,765 Fekete June 5, 1917 1,318,069 Giesler Oct. 7, 1919 1,327,148 Druar Jan. 6, 1920 1,359,198 Rayeld Nov. 16, 1920 1,616,966 Good Feb. 8, 1927 1,668,817 Muir May 8, 1928 1,792,520 Weinhardt Feb. 17, 1931 1,848,987 Anibal Mar. 8, 1932 

